OBDII Catalyst Not Ready

[Sheri]

Hi all,

I went to have my 2009 Honda Fit Sport emissions tested and all of my sensors are ready/passed, except my catalyst sensor. The check engine light is NOT on, but the obd II monitor is kicking back “Not ready” for the catalyst sensor only. I replaced the battery last fall and do regular routine maintenance (oil recently changed, air filter cleaned). Any ideas on what I can do to get this sensor to start registering? I have read some about drive cycles, but haven’t come across a Honda specific drive cycle for the catalyst monitor.

Also, last fill up, I poured some “guaranteed to pass” in the gas tank, but no status change.

Topic

[Shaun Flichel]

Not sure about Hondas but test won’t run on a full tank. It something like 15-85% fuel level that’s required. I’ll search around and see what I find.

[Shaun Flichel]

This is for an accord. Not sure how close it is.
Here is a typical Honda Accord drive cycle. Driving your Honda Accord in the manner below should make the required Emission Monitors “Ready”. Before you start the Drive Cycle make sure your Honda Accord’s fuel level is between 1/4 and 3/4, otherwise the EVAP test won’t run. Make sure to obey all traffic laws while performing the drive cycle.

1. Begin by idling the engine while 2 1/2 minutes. Next idle for another 2 1/2 minutes with the A/C compressor and rear defroster on and while the transmission is in Drive (D); only of automatic transmission. This part of the drive cycle checks the oxygen sensor heater circuits, air pump and EVAP purge system.

2. Turn the A/C compressor off and rear window defroster off and accelerate to 55 mph at half throttle. During this step the OBDII system checks for ignition misfire, fuel trim and EVAP canister purge.

3. Hold at a steady state speed of 55 mph for 3 minutes. The computer will now be testing the EGR system, air injection pump, O2 sensors and canister purge.

4. Decelerate to 20 mph without braking (or depressing the clutch). Once again the computer system will check EGR and purge functions.

5. Accelerate back to 55 to 60 mph at half throttle. During this step the OBDII system will look for misfires, fuel trim and EVAP purge.

6. Hold at a steady speed of 55 to 60 mph for 5 minutes. Catalytic converter efficiency, EGR flow, ignition misfire, fuel trim, EVAP system and oxygen sensors operation will now be checked.

7. Decelerate to a stop without braking (or depressing clutch). The OBDII system will complete the drive cycle at this point.

We recommend completing this drive cycle at least twice in order to insure all required parameters have been met.

[Sheri]

Thanks Shaun! I’m curious if it will work for Fit. A few questions. If it’s just catalyst, do you think full cycle for all parameters has to be completed? Secondly, for step 3, whats the delay between idling and then getting up to 55? It’s tricky to go from idling in park after sitting overnight to immediate highway speed. Hard to think of an area where that’s feasible. And last question, I was considering disconnecting battery to start all from scratch and doing 2 complete drive cycles, but the smog guy advised against that bc it would reset everything. Any suggestions?

[Shaun Flichel]

I think it’s best to leave the battery connected. Do all the steps to get the catalyst test. I may be wrong but I think it tests in the order it does leading up to the catalyst test, like if a step before it fails, it won’t go to the next test. Unsure of that idle thing you mention in step 3, I’m not seeing it.

[Sheri]

Thanks for the advice. I wasn’t sure if each step activated the next sensor in sequence or not. As for step 3, I wasn’t clear and i think what im referring to actually is in step 1 to 2. What I meant was in step 1, you idle and then in 2, you do the a/c, defrost and then it says to accelerate to 55. I’m just trying to figure out realistically where to begin the test in a real-world setting that you can go from idle to immediate highway speed. Start beside freeway so you can immediately accelerate after the idling and a/c, defrost? Because if I start from driveway, its 10 min drive before im able to accelerate to 55. Does that make sense? Thanks again! The drive cycle concept has been a new thing for me to figure out.

[Shaun Flichel]

I don’t think that short drive will affect it. But again I’m not positive.

[Mike T.]

From my personal experience disconnecting the battery and letting the computer reset is the way to go. Many people have no luck with these so called drive cycles. In fact many techs at the dealerships call drive cycles bull.
Many inexpensive OBDll code readers can read when websites are ready for smog. Good luck

[Pete Bagnall]

I know this is an old thread but I thought I’d reply in case anyone else stumbles across the topic and needs some help! I have a 2006 Honda CR-V and live in California. I recently went to smog it and to my surprise it failed due to an incomplete catalyst monitor. This was especially strange because the last time the battery was disconnected was like 1200 miles and a couple months ago! The smog shop turned me away and only suggested driving it a lot to get the test to run. I looked up the drive cycle and did it once or twice a day for a week but it still showed incomplete catalyst every time I plugged in the OBDII. The car ran great and had no codes.
I do all my own car work since I’m the most capable and trustworthy guy I know, so I decided it would be worth the money to start by replacing my coolant temp sensors in case they weren’t accurate enough to initialize the temp criteria for the ecu to run the test.
I replaced them both, one is hidden in the block next to the air box which needed to be removed to access it. The other is also known as a “fan switch” and is in the bottom of the radiator near the middle. You have to drain your coolant to do the fan switch but the whole job was very easy in general.
The very next morning I ran the drive cycle and it completed the catalyst test, 0 codes, good to go. Total cost under $100. I got Duralast sensors from autozone for around $30 each plus a jug of blue coolant because I didn’t want to wait for original Honda sensors from Hondapartsnow.
Glad I went through this because if not, I might not have found Ericthecarguy! Appreciate your videos and info, very good stuff!

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